Polypropylene fibers having improved soil and stain repellency

ABSTRACT

The soil and stain repellency of extruded filaments of a synthetic resin can be improved by incorporating in the resin a small amount, about 1 percent, of an amphipathic compound having from one to four fluoroalkyl groups pendent from an organic radical. The repellency is provided by the fluoroalkyl groups, which tend to be concentrated at the surface of the fiber.

United States Patent Oxenrider et al. Oct. 1, 1974 POLYPROPYLENE FIBERSHAVING [52] US. Cl. 260/93.7, 260/75 H, 260/78 S, IMPROVED SOIL ANDSTAIN 260/88.7 B, 260/94.9 GD R LL [51] Int. Cl. C08f 29/02 [75]Inventors: Bryce C Oxenride-r, Florham Park; [58] Field of Search260/93.7, 94.9 GD 3 ll Woolf Momstown both of Primary ExaminerMelvinGoldstein Attorney, Agent, or Firm-Arthur J. Plantamura [73] Assignee:Allied Chemical Corporation, New

York, NY. [57] ABSTRACT [22] Filed. July 25 1973 The soil and stainrepellency of extruded filaments of a synthetic resin can be improved byincorporating in PP 382,622 the resin a small amount, about 1 percent,of an am- Related Application Data phipathic compound having from one tofour fluoroal- [62] Division of Ser. No. 205,424, Dec. 6, 1971, Pat. Nokyl groups pendent from an Orgamc radical The re- 3,767,625, which is adivision of Ser. No. 867,368, Oct. 17, 1969, Pat. No. 3,646,153.

pellency is provided by the fluoroalkyl groups, which tend to beconcentrated at the surface of the fiber,

3 Claims, No Drawings POLYPROPYLENE FIBERS HAVING IMPROVED SOIL ANDSTAIN REPELLENCY This is a division of application Ser. No. 205,424,filed Dec. 6, 1971 which in turn is a division of application Ser. No.867,368, filed Oct. 17, 1969 now U.S. Pat. Nos. 3,767,625 and 3,646,153respectively.

BACKGROUND OF THE INVENTION This invention relates to synthetic fibershaving im proved soil and stain repellency.

It is desirable to impart soil and stain repellency to fabrics used inapparel, upholstery, draperies and similar applications. The presentmethod used to impart soil and stain repellency to fabrics involvescoating the fabric with an oil and water repellent compound. The coatingis applied using common textile finishing techniques, such as treatingthe fabric with a padding bath of a solution or aqueous dispersion ofthe compound or spraying the surface of the fabric with the compound. Inany case, the operation represents a separate step which must beperformed upon a fabric after it has been dyed or printed. In addition,a subsequent curing step is normally required to set the coating. Thecoating is present on the fabric as a distinct phase which is subject toremoval. Soil which penetrates the coating is not easily removed bylaundering or dry cleaning because the soil becomes trapped beneath thecoating.

Another drawback of the present method is the difficulty inherenttherein of applying a uniform coating to the fabric. The coating tendsto be distributed unevenly on the fabric and to form globules thereon.

SUMMARY OF THE INVENTION We have found that oil and stain repellency canbe imparted to extruded filaments of fiber-forming thermoplastic resinsdirectly by adding certain fluorine containing compounds to the resinfrom which the fibers are prepared. Fibers prepared from the modifiedresin have improved soil and stain repellency and exhibit better stainrelease during laundering and dry cleaning. The fluorocompound additivesof this invention reduce the surface energy of the fiber, but otherwisedo not affect the mechanical (e.g. tensile) properties of the fiber.Consequently, the fibers can be woven into fabrics in the same manner asunmodified fibers, and in addition, can be used to prepare other textileproducts, such as carpets, having improved soil and stain repellency. Aprincipal advantage of this invention is that oil and stain repellencycan be readily imparted directly to the fiber by the fiber manufacturer,thereby eliminating the need for the manufacturer of the ultimatetextile product to apply a repellent coating to the fabric.

The additive is added to the resin in an amount ranging from about 0.1to about 2 percent, preferably about 0.5 to 1.5 percent, based on theweight of the resin.

This small amount of additive causes a substantial lowering ofthesurface energy of the fiber, which is a direct measure of the ability ofthe fiber to repel oil and water borne soil and stain. For example, afiber of unmodified nylon-6 normally has a surface energy of about 46dynes/cm, whereas a fiber of nylon-6 containing 1 percent of an additiveof this invention has a surface energy which is only slightly more thanthat of the additive itself (the additives have surface energies rangingfrom about l0 to 20 dynes/cm.). To explain this phenomenon, it istheorized that the additive migrates to the surface of the fiber as thefiber is extruded to form a boundary layer between the rest of the fibersystem and that which contacts the fiber. This boundary layer is notpermanently removed by scouring, laundering, dry cleaning or dyeing,which indicates that it is stable to use conditions.

In spite of this boundary layer, the fiber can be dyed just like theunmodified fiber, which is surprising in view of the repellent nature ofthe layer.

The fluorocompound additives of this invention are characterized intheir molecular structure in having from one to four fluoroalkyl groups,which provide the repellency, pendent from an organic radical whichserves to make the additive dispersible in the resin. Hence, theadditive is amphipathic in that one segment of the molecule has anaffinity for the resin substrate while the remainder of the molecule,containing the perfluoroalkyl groups, is essentially repellent innature.

In referring to the relationship between the additive and the resin, theterms dispersed and dispersible are used herein to indicate that theadditive and the resin together form a macroscopically homogeneoussingle phase which behaves substantially like the resin alone inprocessing and in forming filaments. As is indicated in Examples 1-4,the additive can be present in the resin as (l) a solution of theadditive in the resin, (2) a random distribution of additive particlesthroughout the resin, or (3) a concentration of additive particles nearthe surface of the resin.

The fluoroalkyl group is the more critical portion of the molecule andhas the formula:

wherein m is an integer from 1 to 16,n is an integer not greater than mfrom 0 to 8, with the sum of m plus n being from 1 to 20, and Y isselected from the group consisting of F;,C and radicals having theformula wherein R and R are fluorine or perfluoroalkyl groups havingfrom one to two carbon atoms, provided that not more than three of the Rand R groups are perfluoroalkyl groups. R, and R are preferablyfluorine. Preferred results are obtained when the total number ofperfluorinated carbon atoms in each fluoroalkyl group is from five to 10and the total number of fluoroalkyl groups is at least two. Forconvenience, the fluoroalkyl group is sometimes referred to hereinafteras R,.

The fluoroalkyl groups are pendent from an organic radical which makesthe additive dispersible in the resin. Since the resin is normallybasically a hydrocarbon containing functional groups, such as amide andester linkages, dispersibility in the resin is achieved by having theorganic radical portion of the additive molecule be of such structure asto effect chemical association, such as hydrogen bonding, between theresin and the organic radical portion. We have found that dispersibilitycan be achieved if the organic radical contains from 1 to 6 carbonylgroups (including the present in acyl groups), from 1 to 21 methylenegroups, from 2 to 8 nitrogen atoms, and from O to 2 phenyl groups,provided the total number of carbon and nitrogen atoms is from to 35. Inaddition, the organic radi cal can contain other atoms, such as oxygenforming an ether linkage, which do not interfere with the dispersibilitydesired to be effected.

in addition to having the foregoing chemical structure, the additivemust also possess certain physical properties. The additive must besubstantially thermally stable at the temperature at which the filamentis extruded. This temperature normally is within the range of 200 to 350C. An additive is thermally stable if it survives the extrusion processwithout forming undesirable decomposition products and withoutdecomposing to such an extent as to lose an appreciable amount ofeffectiveness in imparting soil and stain repellency to the filament. Inaddition to being thermally stable, the additive must also benonfugitive, i.e., not

appreciably volatile, at the temperature of extrusion,

otherwise it would escape from the filament. A further requirement isthat the additive must itself have a low surface energy in order toimpart a low surface energy to the filament. To be suitable, theadditive must have a surface energy of less than dynes/cm.

We have identified the following classes of compounds as being suitableadditives in the practice of this invention:

A. Monoamides of the formula wherein R is an alkyl diradical of one toeight carbon atoms, an alkylene diradical of two to eight carbon atoms,or a phenyl diradical;

B. Diamides of the formula wherein R is an alkyl diradical of one toeight carbon atoms, an alkylene diradical of two to eight carbon atoms,a phenyl diradical, or a dicarboxy phenyl diradical having the formula CHexahydrotriazines of the formula ll I ll RrCNHgNHCRr 20 wherein R ishydrogen, trichloromethyl, or a phenyl radical; E. lsocyanurate estersof the formula F. lsocyanurate esters of the formula N 0 ir 1 0 ll I(Riomoomcm NOHzCHZOoRi G. Substituted ureas of the formula H.Substituted ureas of the formula ll RiCNHCHzCHz (M) if CHzCHrNHCRrN-CNH-R-NHC-N RrCNHCHgCHz CHzcHzNHtlIllRr ll 0 O Mae ani;aaarmmiearararea; l3carb6n atoms, an alkylene diradical of two to 13 carbon atoms,or an aryl, aralkyl, or aralkylene diradical of six to 13 carbon atoms;

J. Substituted oxamides of the formula 0 0 II I moNHomom o o omcmmzrbmwith a cyclic 'aaiayd'rraeaf'ihe farinma'" *w'h'ereinmame meaningpreviously givrifo r the ad- '7 ditives of Class A. The reaction iscarried out in an inert solvent, such as acetone, at temperaturesranging from room temperature to the reflux temperature of the reactionmixture. The additives of Class A, as novel compositions of matter, arethe subject of copending application Ser. No. 867,371, now U.S. Pat. No.3,754,026, filed concurrently herewith, the pertinent subject matter ofwhich is incorporated herein by reference.

The cyclic anhydride reactants are well known materials. The triazareactants are readily prepared by reacting a lower alkyl ester of anacid having the formula R,COOH with an amine having the formula NH (Cl-lNH(CH Nl-l wherein R, has the meaning given for the compounds of thisinvention. Esters derived from acids having the formula R,COOl-l whereinthe Y group of the R, component is F;,C are well Maximum use Surfacetemperenergy a e, dynes/ Class B; R 0. cm.

A C: 1 F2)a -(CH2)a- 225 13. 5 C3F1O (CFflr- (CH2)I 250 13. 5 CFs(CFz)n2)a 200 15. 5

B C3F7O (CFg)3 250 14. 1

CFACFM- 300 12. 2 C3F7O (OFzh- 250 3 1 2)4 225 CF3(OF (monoester) 25015. 5 CFa(CFn)o-(di65t8l) 260 12. 5 CF3(CF2)6(tYiBSt6l) 300 13. 0 O FO(CF )2(monoestei-) 250 16. 5 CaF1O(CF )@(d1estez-) 250 18-14 F CF(CFz)a(d16StBr) 260 14 G CF3(CF;)Q- 225 16 H F2)o- R1 is H, R: is gienyl225 16. 5 a(CF2)e R1 and R are 225 16. 1

I CF3 CF 0- 260 15. 8

CF:(CF2)0- -(CH1)s 260 15 CF3(CF2)u 260 13 5 J CFa(CF)t- 300 15 1 Nottested.

PREPARATION OF ADDITIVES iiib'wh' materials and can be made from theacids, which are generally available commercially. Acids wherein Y hasthe formula can be prepared from a telomer halide having the formulawherein R and R have the afore-stated meanings, w and x are integersindicating the respective degrees of telomerization, and E is bromine oriodine. These telomer halides and their method of preparation aredescribed in US. application Ser. No. 633,359 filed Apr. 25, 1967, nowUS. Pat. No. 3,514,487 the pertinent subject matter of which isincorporated herein by reference. The telomer halides are prepared byreacting telogens of the formula FOR-2 FCOCFzCFzE FRz wherein n is O canbe prepared by reacting the corresponding telomer halide with ICN or(CN) at pressures above atmospheres and at temperatures above 300C. toform the nitrile, followed by hydrolysis of the nitrile in accordancewith conventional methods to form the acid. Acids wherein n is greaterthan zero can be prepared by reacting the corresponding telomer halidewith an alkali metal cyanide in the presence of dimethyl sulfoxide attemperatures between 60 and 100C. to form the nitrile, from which theacid can be prepared in accordance with conventional methods. The acidcan also be prepared (regardless of whether n or O or greater) byreacting the telomer halide with sulfur trioxide, followed by hydrolysisof the reaction product to obtain the acid. By this method. the acidcontains one less carbon atom than the telomer halide from which it wasprepared. Also, the acid thus formed can be converted to thecorresponding telomer iodide for further telomerization by reaction withalkali-free silver oxide to form the silver salt, followed by reactionof the silver salt with powdered iodine to form the telomer iodide. Bythis method, acids having either an odd or even number of hydrocarbyl orfluorocarbyl groups can be prepared.

The additives of Class B are prepared by reacting the triaza compoundreferred to above with a diacid chloride having the formula ClOCRCOCl,where R has the meaning previously given for the additives of Class B,with the exception that R is not a dicarboxy phenyl radical. In order toprepare the additive of Class B wherein R is a dicarboxy phenyl radicalhaving the formula of a diacid chloride. The reaction is carried out inan inert solvent, such as acetone, at temperatures ranging from roomtemperature up to the reflux temperature of the reaction mixture. Theadditives of Class B, as novel compositions of matter, are the subjectof copending application Ser. No. 867,373, now US. Pat. No. 3,697,562,filed concurrently herewith, the pertinent subject matter of which isincorporated herein by reference.

The additives of Class C are prepared by reacting a compound of theformula R,CN with trioxane in the presence of a catalytic amount, about1 percent by weight, of a strong acid, such as H 50 The additives ofClass C, as novel compositions of matter, and their method ofpreparation are the subject of copending application Ser. No. 867,370,now US. Pat. No. 3,657,235, filed concurrently herewith. Nitrilereactants having the formula CF,,(CF ),,,(CH ),,CN are known compoundsand can be prepared from commercially available materials in accordancewith known methods. Nitrile reactants having the formula can be preparedfrom telomer halides in accordance with the methods described in thepenultimate paragraph above, which methods are described in greaterdetail in Canadian Patent Nos. 823,673 and 823,674, corresponding toU.S. Ser. Nos. 721,115 and 721,117 now US. Pat. Nos. 3,697,564'and3,706,773, respectively, both US. applications having been filed on Apr.12, 1968, the pertinent subject matter of which is incorporated hereinby reference.

The additives of Class D are prepared by reacting a nitrile of theformula R,CN with an aldehyde of the formula RCHO, wherein R has themeaning previously given for the additives of Class D, in the presenceof an acid catalyst. Additives having the I formula R,CONHCH NHCOR areobtained as by-products in the preparation of the additives of Class C.The additives of Class D, as novel compositions of matter, are thesubject of copending application Ser. No. 867,372, now US. Pat. No.3,786,093, filed, concurrently herewith, the pertinent subject matter ofwhich is incorporated herein by reference.

The additives of Class E are prepared by reacting tris-(Z-carboxyethyl)isocyanurate with an alcohol of the formula R,OH underanhydrous conditions, using as a solvent a perfluorocarboxylic acidhaving up to eight carbon atoms. The reaction product contains a mixtureof mono-, diand triesters. The additives of Class E, as novelcompositions of matter, and their method of preparation are moreparticularly described in copending application Ser. No. 808,681, filedMar. 19, 1969 now U.S. Pat. No. 3,629,255, the pertinent subject matterof which is incorporated herein by reference.

The additives of Class F are prepared by reacting tri(-2-hydroxyethyl)isocyanurate with an acid having the formula R,COOH underanhydrous conditions using an inert solvent. The reaction productcontains a mixture of mono-, diand triesters. The additives of Class F,as novel composition of matter, and their method of preparation are moreparticularly described in copending application Ser. No. 808,681, filedMar. 19, 1969, the pertinent subject matter of which is incorporatedherein by reference.

The substituted urea additives of Classes G, H, and I are readilyprepared by refluxing the triaza compound previously referred to withthe appropriate isocyanate or diisocyanate in a solvent such as acetone.The appropriate isocyanate or diisocyanate compounds are well known inthe art. I

The additives of Class I are prepared in accordance with the method usedto prepare the additives of Class B using oxalyl chloride as the diacidchloride reactant.

PREPARATION OF FIBERS The filaments of the invention are prepared byforming an intimate blend of the additive and the resin and thenextruding the blend into filaments in accordance with methods known tothe art. The method of forming the blend is not critical. The blend canbe formed by treating the resin in powder form with a solution of theadditive and then extruding and pelletizing the treated resin after ithas been allowed to dry. Another method of forming the blend comprisesdry blending the additive with the resin in powder form and then workingthe mixture on a rubber mill or similar device.

The incorporation of the additive into the resin does not interfere withthe formation of the filament or fibers drawn therefrom. Although thefluoroalkyl groups of the additive tend to render the additiveincompatible with the resin, the additive does not distrub the normalmacroscopic homogeneity of the polymer phase. This is surprising in viewof the cirtical rheological conditions involved in the extrusion offilaments and the drawing of fibers.

By examining the filaments of this invention with the aid of aphotomicroscope, we have found that the additive can be present in thefilament in any of the following ways: (a) as finely dispersed, randomlydistributed particles in the resin matrix, (b) as finely dispersedparticles concentrated at the fiber surface, as an invisible solution inthe resin matrix. But regardless of how the additive is present, iteffectively imparts antisoiling and antistaining properties to thefilament.

In some instances, the surface energy of the filament can be loweredeven further by annealing the filament after it has been extruded.Annealing increases the mobility of the additive and allows it tomigrate to the surface of the filament. Annealing is preferably carriedout at the highest practical temperature, which is normally just belowthe temperature at which degradation of the fiber occurs, and for anoptimum period which can readily be determined for each particular fiberby simple experiment. For fibers prepared from nylon-6, the preferredperiod is two to four hours. Annealing is normally performed in an inertatmosphere, such as nitrogen, to prevent oxidative degradation of thefiber.

This invention is generally applicable to filaments prepared from anyfiber-forming thermoplastic resin, such as polypropylene, polyamide,polyester, polyacrylonitrile and blends thereof. Particularly goodresults are obtained with polyamide and polyester resins (includingblends" thereof), especially with polyamide resins.

When nylon-6or nylon-66 is the resin, especially preferred results areobtained using the additive l,7-bis(4- perfluoroisopropoxybutyryl l,4,7-triazaheptane monoglutaramide.

The practice of this invention is illustrated by the following examples.

EXAMPLE 1 Preparation of Additive 60.4 grams of 1,7bis(4-perfluoroisopropoxybutyryl)- l,4,7-triazaheptane were dissolved in250 ml of acetone. To this solution was added a solution of 8.35 gramsof glutaric anhydride in 100 ml of acetone. The reaction mixture wasstirred at 50C for one hour, then cooled and diluted with water. Theproduct layer was dissolved in ether, washed with water, treated withcharcoal and finally dried over MgSO,. The product obtained afterevaporation of the ether solution was 1,7bis(4-perfiuoroisopropoxybutyryl)-l ,4,7-triazaheptane monoglutaramide,a waxy solid having a melting point of 80C, and was obtained at a yieldof about 100 percent. Preparation of Fibers Commercially availablepellets of nylon-6 were comminuted with Dry Ice. The additive wasdissolved in acetone and applied to the comminuted nylon. The coatednylon was dried at C and 5 mm. Hg overnight, then extruded intomonofilament and pelletized. The pellets were then extruded into fiberfrom a Reifenhauser extruder using a 7 hole, 20 mil die and a screenpack as filter. The resin was extruded at a temperature of about 260Cand at an extrusion rate of 60 to feet/minute. The extrudate wasquenched by an air stream at 16C. The denier was precontrolled by therate of fiber take-up 'with subsequent variable melt draw. Filaments of60 denier, l6 denier and 8 denier were prepared by this technique. Thefilaments were subsequently drawn at a ratio of 4:1. The filamentscontained 1 percent by weight of the additive. Fiber Tests The surfaceenergy of the filaments was measured and found to be as follows:

Undrawn Denier Surface Enerzv dvnes/cm.

Drawn 4:1 l822 4 27-32 2 35-40 In comparison, the surface energy ofunmodified nylon- 6 fiber is about 46 dynes/cm. The surface energy of afiber directly reflects its ability ot repel oil and water borne soiland stain.

The lower surface energy of the 60 denier fiber is presumably due to themore favorable surface to volume ratio of the fiber, which allows agreater concentration of the additive at the surface. However, we foundthat increasing the amount of additive to 1.5 percent effected nofurther decrease in the surface energy of the fibers, and thatincreasing the level to 2 percent tended to cause dripping in thespinning operation.

Photomicrographs of the fibers revealed no visible additive particles,indicating that the additive was either dissolved or very finelydispersed in the resin matrrx.

Annealing at 120150C for two to four hours in an inert atmosphere causeda lowering of the surface energy of the undrawn 16 and 8 denier fibersto 18-22 dynes/cm. and -27 dynes/cm. respectively. This indicates thatthe additive is capable of migrating through the resin matrix to thesurface.

Neither scouring the fibers nor wiping them with CC], produced anychange in the surface energy.

The fibers were dyed according to standard procedures using variouscommercially available dyes, such as Necelan Blue FFRD, C.l. DisperseBlue 3 and Kiton Fast Blue CB. It was found that the fibers containingthe additive were as receptive to the dye as unmodified fibers and thatthe dye was just as 'colorfast when the fibers were subjected tolaundering and drycleaning. Furthermore, dyeing had no adverse effect onthe surface energy on the fibers containing the additive.

A test cloth was prepared using the 15 denier fiber and the ability ofthe cloth to resist common household stains, including catsup, Frenchdressing, spinach, chocolate and hot coffee, was compared with that of acontrol cloth prepared from unmodified nylon-6 fiber. The cloth preparedfrom the modified fiber had better stain resistance and also exhibitedbetter stain release during subsequent laundering.

EXAMPLE 2 Preparation of Additive To 202 grams perfluorooctanoylchloride were added 45 ml anhydrous methanol. The temperature rose toabout 65C. as HCl was evolved. An additional liter of methanol was addedover a period of about one hour. The mixture was then heated at about65C. for about 90 minutes. The reaction product was separated from thelayer of unreacted methanol, washed with water, dried overnight over NaSO crystals, filtered and distilled. 164 grams of methylperfluorooctanoate were recovered.

To the methyl ester prepared above were added 20.6 gramsdiethylene-triamine dropwise, with the temperature rising to about C.The mixture was maintained at that temperature for one hour withstirring. The reaction product solidified as the mixture cooled to roomtemperature. The product was recrystallized from acetonitrile and driedovernight at 60C. and 1 mm Hg. 135 grams of 1,7bis(perfluorooctanoyl)-1,4,7- triazaheptane were recovered. v

To a solution of 8.9 grams of the triaza compound prepared above in 40ml of acetone were added a solution of 1.5 grams glutaric anhydride in10 ml of acetone. The mixture was stirred at room temperature for about20 minutes, at which time a haze, indicating a precipitate, developed.The mixture was stirred for another four hours and then allowed to standovernight. The product was recovered by filtration, washed with water,and vacuum dried. 9.7 grams of 1,7 bis(perfluorooctanoyl)-l,4,7-triazaheptane monoglutaramide were recovered.

Preparation of Fibers Fibers were prepared using 1.0 percent of theadditive prepared above. An undrawn filament having a diameter of 16mils (about 1300 denier) had a surface energy of less than 18 dynes/cm.When the filament was drawn 4:1, the resulting fiber had a surfaceenergy of 22 dynes/cm.

Photomicrographs of the fibers revealed that the additive is present asa distinct band under the skin of the fiber. This is in contrast toExample 1, where the additive was not visible at all.

EXAMPLE 3 Preparation of Additive 985 grams of 1,7bis(perfluorooctanoyl)-l ,4,7- triazaheptane and 143 grams of triethylamine were dissolved in 5 liters of acetone. To this solution was addeddropwise a solution of 1 12 grams of isophthalylchloride in one liter ofacetone. The reaction mixture was stirred at 50C for 4 hours, thencooled to room temperature. The resulting precipitate was recovered,washed with acetone and was recrystallized from hot ethanol. The productwas 1,7 bis(perfluorooctanoyl-l ,4,7- triazaheptane isophthalamide, awhite solid having a melting point of 178C, and was obtained at a yieldof percent. Preparation of Fibers Fibers were prepared using 0.1, 0.25,0.50, and 1.0 percent of the additive prepared above. The surface energyof the fibers is tabulated below:

Surface Energy, dynes[cm.

Concentration of Additive, Undrawn( 16 mils) Drawn(4 mils) ergy.

EXAMPLE 4 Preparation of Additive l,7-Bis(perfluorooctanoyl)-l,4,7-triazaheptane adipamide was prepared following the general methodof Example 3, except adipyl chloride was substituted forisophthalylchloride. The product was a white solid having a meltingpoint of 190195C. Preparation of Fibers Fibers were prepared using 1percent of the additive prepared above. An undrawn filament of 60 denierhad a surface energy of less than 18 dynes/cm. When the filament wasdrawn 4:1, the resulting fiber had a surface energy of 25 dynes/cm.

Photomicrographs of the fibers revealed that the additive was present asa random distribution of particles throughout the resin matrix.

EXAMPLE 5 Preparation of Additive A mixture of 258 grams of12,12,13,l3,14,14,l5,15- octafiuoro-l5-heptafluoroisopropoxypentadecanoic acid and 410 grams of thionylchloride was heated to reflux over a period of 40 minutes and thenmaintained at reflux for 3 hours. The reaction mixture was cooled toroom temperature and excess thionyl chloride was evaporated off undervacuum to give 267 grams of crude acid chloride.

To a stirred solution of the crude acid chloride in 750 ml of benzene atC was added 24.2 grams of N,N- dimethylaniline over a period of minutes.A solution of 32.5 grams of activated sodium azide in 100 ml of waterwas then added dropwise over a period of minutes as the temperature wasmaintained at less than 10C. The reaction mixture was stirred for 30minutes at 5-10C, and then at room temperature for 90 minutes. Thebenzene layer was separated, extracted with cold 10 percent hydrochloricacid, dried over sodium sulfate, heated to reflux and maintained atreflux for two hours. The product was (CF;,) CFO(CF (CH NCO, a colorlessoil having a boiling point of 1 19C at 0.5 mm Hg. This compound and itsmethod of preparation are the invention of our colleague .1. Murray andare the subject of US. Pat. No. 3,657,306.

The compound 12,12,13,13,14,14,15,15-octaflu0ro-15-heptafluoroisopropoxypentadecanoic acid is a known compound, beingdescribed in Canadian Patent Nos. 823,673 and 823,674, corresponding toUS. Ser. Nos. 721,115 and 721,117 now US. Pat. Nos. 3,697,564 and3,706,773, respectively, both US. applications having been filed on Apr.12, 1968. Preparation of Fibers Fibers were prepared using 1 percent ofthe additive prepared above. An undrawn filament of 60 denier had asurface energy of 27 dynes/cm. When the filament was drawn 4:1 theresulting fiber had a surface energy of 32-35 dynes/cm. However, whenthe fiber was annealed at 130-140C for two hours, the surface energy wasreduced to 27 dynes/cm. We theorize that during the drawing operationthe additive is not sufficiently mobile to keep replenishing the newlygenerated surfaces, but that during the annealing step the additivemigrates to the surface to render it equivalent to the surface of theundrawn fiber.

EXAMPLE 6 Preparation of Additive 65 grams of C;,F O(CF CH CH CN and 0.7grams concentrated sulfuric acid in 100 m1 of carbon tetrachloride werewarmed to reflux. A solution of 4.6

grams of trioxane in ml of carbon tetrachloride was added dropwise overa period of two hours. The reaction was continued at reflux for anadditional two hours. The product precipitated upon cooling, was washedwith water, dried, recrystallized from carbon tetrachloride andidentified as 61.0 grams of white product, melting point 8183C, wereobtained at a yield of 89 percent. From the mother liquor were recovered7.0 grams of the bisamide Preparation of Fibers The two compoundsprepared above are used in accordance with this invention to preparefibers having improved soil and stain repellency.

EXAMPLE 7 Preparation of Fibers The additive prepared above is used inaccordance with this invention to produce fibers having improved soiland stain repellency.

EXAMPLE 8 Preparation of Additive 89 grams (0.01 mol) of1,7-bis(perfluorooctanoyl)- l,4,7-triazaheptane and 1.20 grams (0.01mol) of phenylisocyanate were reacted in 50 ml of acetone for 5 minutesat reflux temperature. The reaction mixture was left standing at roomtemperature overnight. The mixture was diluted with an excess of water,which caused the product to separate as an oily layer which l l6gradually solidified. The product was filtered off, air wiikifikiafiai'ky'r'dir'ma'6? one to eight carbon dried, and recrystallized fromethanol-water. The prodatoms, an alkylene diradical of two to eightcarbon uct, a white solid having a melting point of l 15l 18C, atoms, ora phenyl diradical; was obtained at a 95 percent yield and wasidentified b. diamides of the formula as N,N-bis(perfluorooctanamidoethyl)-N-phenyl 5 urea. W W H Mm W W M Preparation of Fibers Theadditive prepared above is used in accordance L with this invention toproduce fibers having'improved soil and stain repellency.

v R('C-NHGHZCHZ CHzCH1NHC-Rl EXAMPLE 9 1 ll (i The additive having theformula pared in 98 percent yi ld by r ti wherein R is an alkyldiradical of one to eight carbon C F O(CF C1-l N1-l with atoms, analkylene diradical of two to eight carbon atoms, a phenyl diradical, ora dicarboxy phenyl diradi- CHNCHOHhEfl) cal having the formula Theadditive is suitable for use in this I f 20 EXAMPLE 10 The additivea-(perfluorooctanoamido)caprolactam, melting point 159C, was prepared in64 percent yield by reacting methyl perfluorooctanoate with a-aminocaprolactam. The additive is suitable for use in this invention toimpart soil and stain repellency to extruded h h d n-i i f th f lsynthetic fibers.

EXAMPLE 11 3 Fibers were prepared from a blend of percent (i=0polyethylene terephthalate and 70 percent nylon-6 1; containing 0.5percent of the additive of Example 3. An 0 I 0 undrawn filament having adiameter of 16 mils had a g E surface energy of less than 18 dynes/cm.When the fiber was drawn 4:], the resulting fiber had a surface energyof 22 dynes/cm.

EXAMPLE l2 drbisamides ofthe formula Fibers were prepared frompolypropylene containing 1 percent by weight of 1,7bis(perfluorooctanoyl)-4- R stearoyl-l,4,7-triazaheptane. An undrawnfilament of moNHoNHcRi 60 denier had a surface energy of less than 18dynes/cm. A control fiber containin no additive had a Surface energy of22 dyneS/Cm g R 15 hydrogen, trichloromethyl or a phenyl EXAMPLE 13 e.isocyanurate esters of the formula Fibers were prepared frompolyethylene terephthalate containing 1 percent of the additive ofExample 3. An undrawn filament of 60 denier had a surface energyCIFHZCECOOHPRO of 27 dynes/cm. When the filament was drawn 4:1, the N\resulting fiber had the same surface energy, 27 dy- O =0 nes/cm. Acontrol fiber of polyethylene terephthalate (RQHOOCCHzCHg-N NCH,CH,COOR|containing no additive had a surface energy of 42 dynes/cm. 0

We claim:

1. An extruded filament of a fiber-forming polypropyl ene havingdispersed therein from about 0.1 to 1 about 2 percent based on theweight of the polypropylene of an additive which improves the soil andstain repellency of the filament, said additive being selected from thegroup consisting of mfrisocyanurate esters of the formula g. substitutedureas of the formula h. substituted ureas of the formula RicNHcmoHz i.substituted ureas of the formula wherein R is an alkyl diradical of oneto 13 carbon atoms, an alkylene diradical oftwo to 13 carbon atoms, oran aryl, aralkyl or aralkylene diradical of six to 13 carbon atoms;

j. substituted oxamides of the formula (1 itiiimiou'zonz cmonmm i-m NCCNRrCNIICHzCI h anatomic-'12,

R, being, in each of the above formulas, the fluoroalkyl group havingthe formula wherein m is an integer from 1 to 16, n is an integer notgreater than m from O to 8, with the sum of m plus n being from 1 to 20,and Y is selected from the group consisting of F C- and radicals havingthe formula wherein R and R are fluorine or perfluoroalkyl groups havingfrom one to two carbon atoms, provided that no more than three of the Rand R groups are perfluoroalkyl groups, said additive further having asurface energy of less than 20 dynes/cm. and being thermally stable andnonfugitive at the temperature at which the filament is extruded.

2. The filament of claim 1 wherein the R, group has from 5 to 10perfluorinated carbon atoms.

3. The filament of claim 2 wherein the additive is present in an amountof from 0.5 to 1.5 percent by weight based on the weight of thepolypropylene.

mg C UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,839,312 Dated October l, 1974 Inventor(s) Bryce C. Oxenrider and CyrilWoolf It is certified that after appears in the shove-identified patentand that said Letters Patent are hereby corrected as shown below:

Column 5, line 42, "C3H7O..-." should be C F7O...

Column 7, line 38, "OsF" should be CsF i li 67, "01"" first occurrenceshould be 1s A Co'lumnlZ, .line 41, ."bis(perfluorooctanoyl-l,4,,7"'a

should be bis(perfluorooctanoyl)-l,4', 7

Claim 1, column l6 j line 66, N. should be l a 1 v Claim 1, columnl7',". line ll, should be 0 I N-C-N u N-C-N Signed and sealed this 11thday of February l 975.

(SEAL) v Attest:

C. MARSHA-LL DANN RUTH C. MASON I e Commissioner of Patents AttestingOfficer I and Trademarks

1. AN EXTRUDED FILAMENT OF A FIBER-FORMING POLYPROPYLENE HAVINGDISPERSED THEREIN FROM ABOUT 0.1 TO ABOUT 2 PERCENT BASED ON THE WEIGHTOF THE POLYPROPYLENE OF AN ADDITIVE WHICH IMPROVES THE SOIL AND STAINREPELLENCY OF THE FILAMENT; SAID ADDITIVE BEING SELECTED FROM THE GROUPCONSISTING OF
 2. The filament of claim 1 wherein the Rf group has from 5to 10 perfluorinated carbon atoms.
 3. The filament of claim 2 whereinthe additive is present in an amount of from 0.5 to 1.5 percent byweight based on the weight of the polypropylene.